HPO:

GeneReviews:

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Penetrance: penetrance is complete in homozygotes with both alleles having full-penetrance gaa repeat expansions and in compound heterozygotes for a full-penetrance gaa expansion in one allele and a fxn pathogenic variant in the other allele. however, because of wide variability in the size of pathogenic expanded alleles, and for other unknown reasons, onset can range from before age five years to older than age 50 years. this variability in age-dependent penetrance can occasionally occur within the same sibship...

Summaries for Friedreich Ataxia

NINDS:49 Friedreich's ataxia is a rare inherited disease that causes progressive damage to the nervous system and movement problems. Neurological symptoms include awkward, unsteady movements, impaired sensory function, speech problems, and vision and hearing loss. Thinking and reasoning abilities are not affected.Impaired muscle coordination (ataxia) results from the degeneration of nerve tissue in the spinal cord and of nerves that control muscle movement in the arms and legs. Symptoms usually begin between the ages of 5 and 15 but can appear in adulthood or later. The first symptom is usually difficulty in walking. The ataxia gradually worsens and slowly spreads to the arms and then the trunk. People lave loss of sensation in the arms and legs, which may spread to other parts of the body. Many people with Friedreich's ataxia develop scoliosis (a curving of the spine to one side), which, if severe, may impair breathing. Other symptoms include chest pain, shortness of breath, and heart problems. Some individuals may develop diabetes. Doctors diagnose Friedreich's ataxia by performing a careful clinical examination, which includes a medical history and a thorough physical examination. Several tests may be performed, including electromyogram (EMG, which measures the electrical activity of cells) and genetic testing.

Genetics Home Reference:25 Friedreich ataxia is a genetic condition that affects the nervous system and causes movement problems. People with this condition develop impaired muscle coordination (ataxia) that worsens over time. Other features of this condition include the gradual loss of strength and sensation in the arms and legs; muscle stiffness (spasticity); and impaired speech, hearing, and vision. Individuals with Friedreich ataxia often have a form of heart disease called hypertrophic cardiomyopathy, which enlarges and weakens the heart muscle and can be life-threatening. Some affected individuals develop diabetes or an abnormal curvature of the spine (scoliosis).

NIH Rare Diseases:48 Friedreich ataxia is an inherited condition that affects the nervous system and causes movement problems. people with this condition develop impaired muscle coordination (ataxia) that worsens over time. other features include the gradual loss of strength and sensation in the arms and legs, muscle stiffness (spasticity), and impaired speech. many individuals have a form of heart disease called hypertrophic cardiomyopathy. some develop diabetes, impaired vision, hearing loss, or an abnormal curvature of the spine (scoliosis). most people with friedreich ataxia begin to experience the signs and symptoms around puberty. this condition is caused by mutations in the fxn gene and is inherited in an autosomal recessive pattern.
last updated: 5/22/2015

MedlinePlus:38 Friedreich's ataxia is an inherited disease that damages your nervous system. the damage affects your spinal cord and the nerves that control muscle movement in your arms and legs. symptoms usually begin between the ages of 5 and 15. the main symptom is ataxia, which means trouble coordinating movements. specific symptoms include
difficulty walking
muscle weakness
speech problems
involuntary eye movements
scoliosis (curving of the spine to one side)
heart palpitations, from the heart disease which can happen along with friedreich's ataxia
people with friedreich's ataxia usually need a wheelchair 15 to 20 years after symptoms first appear. in severe cases, people become incapacitated. there is no cure. you can treat symptoms with medicines, braces, surgery, and physical therapy.
nih: national institute of neurological disorders and stroke

UniProtKB/Swiss-Prot:70 Friedreich ataxia: Autosomal recessive, progressive degenerative disease characterized by neurodegeneration and cardiomyopathy it is the most common inherited ataxia. The disorder is usually manifest before adolescence and is generally characterized by incoordination of limb movements, dysarthria, nystagmus, diminished or absent tendon reflexes, Babinski sign, impairment of position and vibratory senses, scoliosis, pes cavus, and hammer toe. In most patients, FRDA is due to GAA triplet repeat expansions in the first intron of the frataxin gene. But in some cases the disease is due to mutations in the coding region.